Hose for conveying pressurized medium is usually reinforced with wire or fabric material against blow out and expansion. However, when such conventional hose is employed in vacuum applications the hose will tend to collapse as the reinforcing sheaths and covers do not effectively resist inwardly directed radial forces, and such hose collapse is particularly present in larger sizeshoses such as those of three inch diameter and greater. Special purpose hydraulic hose has been developed for hydraulic vacuum applications such as used in pump suction lines and the like, and such vacuum hoses normally incorporate coiled metal components embedded within the hose material, or directly engaging the hose inner diameter, to prevent hose collapse. However, such suction hose is of a relatively specialized nature, expensive to manufacture and only available in a relatively limited number of sizes and materials.
Hydraulic hose capable of confining pressurized fluids is commercially available in a wide range of sizes and materials for handling various types of fluids, and it is known to use hose insert devices with such conventional hose in those applications wherein such hose is used to convey fluids at subatmospheric pressures. For instance, it has been the practice of the assignee to employ a stainless steel or beryllium copper spiral coil within its larger diameter flexible wall hose when used in hydraulic vacuum applications. However, such hose reinforcing coil is difficult to assemble within the hose as coil spacing members must be used in conjunction with the coil to maintain axial coil separation, and the presence of the coils within the hose produces adverse fluid flow characteristics and turbulence. Further, in submarine applications utilizing vacuum hose spiral inserts the presence of the metallic spiral produces undesirable noise as the end of the spiral wall engage the hose nipples, and in this particular application sound attenuation is of utmost importance.